Zenoah Velocity Stack
Howard
installed on a Zenoah.
I have a G20 I'm going to mount on a Hangar 9 P-47 ARF 60 size that I'm
putting together. I'm not sure that I want to cut a hole in the cowl for the
stack.
Anyone have this combination? It's recommended by Hoizon as a good combo,
but I'm wondering. The engine with muffler and carb with velocity stack
installed is 7 inches. The fuse at it's widest part is just a tad over 6 3/4
inches. Cutting holes all over the cowl for muffler, velocity stack, choke
lever, spark plug, adjustment screws just kills the scale looks.
This is my first gas engine. I'm not experienced with these. How necessary
is the choke in getting it started? I'm in Central Florida so the cold days
are rare.
Thanks for your 2 cents.
Howard
JJVB
necessity. I used one mainly to be able to choke the engine without
having a choke lever rigged. I just cover the stack and flip a couple
of times.
Yes, you must choke a gas engine.
John VB
Jim
stack. The stack is used to prevent fuel from being 'sucked out' of the
venturi of the carb by the air moving past the carburetor.
"Howard" <howardh1951-at-hotmail.com> wrote in message
news:4683255e$0$4644$4c36...@roadrunner.com...
Morgans
"Jim" <> wrote
> So long as the intake of the carb is inside the cowling, you don't need
> the stack. The stack is used to prevent fuel from being 'sucked out' of
> the venturi of the carb by the air moving past the carburetor.
That is one reason.
Others are that it keeps fuel from burbling out all over the place while the
engine is at idle, and that it gives a little more HP at high power settings
by keeping air flow going at better speeds and pressure, by acting somewhat
as ram air; that is the air column gets moving, then the intake cycle stops,
stopping the air for an instant, and a pipe around the intake contains the
moving air until the intake cycle begins again.
I think there is a noticeable improvement in performance with a velocity
stack. I have no data, just "I thinks." <g>
--
Jim in NC
Martin X. Moleski, SJ
>"Jim" <> wrote
>That is one reason.
I have the same lack of data and the same thoughts.
I think your idea of how it modifies and improves the
pulses of air in the venturi is correct.
This page suggests that sucking back the gas that would have
been lost is part of the big picture:
http://en.wikipedia.org/wiki/Velocity_stack
I have one (1) US Engine with a nice velocity stack
on it. It looks great. Haven't flown the engine
yet. Still searching for the right airframe. Ran
it just once on a test stand. Its chainsaw heritage
came through LOUD and clear!
It seems to me that some of the racing cars from the
60s or 70s had velocity stacks on them--I can't
imagine what else they would be:
http://www.mlodeent.com/CANAM/07acar68.jpg
Marty
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Martin X. Moleski, SJ
I think your idea of how it modifies and improves the
pulses of air in the venturi is correct.
This page suggests that sucking back the gas that would have
been lost is part of the big picture:
http://en.wikipedia.org/wiki/Velocity_stack
I have one (1) US Engine with a nice velocity stack
on it. It looks great. Haven't flown the engine
yet. Still searching for the right airframe. Ran
it just once on a test stand. Its chainsaw heritage
came through LOUD and clear!
It seems to me that some of the racing cars from the
60s or 70s had velocity stacks on them--I can't
imagine what else they would be:
http://www.mlodeent.com/CANAM/07acar68.jpg
Marty
--